HPE 844471-B21 Compatible 25G SFP28 to SFP28 DAC Cable 50cm (1.6ft) Passive Direct Attach Copper Twinax Cable-HYTOPTODEVICE

The HYTOPTODEVICE 844471-B21 DAC SFP28 25G  is pre-programmed for 100% "Plug-and-Play" operation with:

• HPE ProLiant Servers: DL360, DL380, DL560, and ML350 (Gen9, Gen10, Gen10 Plus, and Gen11).

• HPE Apollo & Synergy Systems: High-density compute modules with 25G SFP28 support.

• HPE Ethernet Adapters: * HPE Ethernet 10/25Gb 2-port SFP28 (640SFP28, 631SFP28, etc.).

  • HPE BCM957414 / Mellanox ConnectX-4 Lx/ConnectX-5 25G adapters.

• HPE StoreFabric: SN2010M, SN2100M, and SN2410M 25GbE switches.

• Operating Systems: Fully supported in HPE iLO 5/6, Comware V7, and ArubaOS-CX.

• ToR Server Aggregation: Connecting HPE ProLiant Gen10 servers to an HPE StoreFabric or Aruba 8325 switch located in the same rack.

• Ultra-Low Latency Stacking: Using the 0.5m length for tight-radius switch stacking where minimal signal travel time is required.

• HCI & NVMe Storage: Providing the high-bandwidth 25Gbps backplane for HPE SimpliVity or HPE Alletra storage nodes.

• HPE BladeSystem Uplinks: Linking Virtual Connect 25G modules to core switches within a 0.5m radius to improve cable management.

Connectivity Solutions(Applications)：

Scenarios 1:25G-to-25G Link for Switch-to-Switch

Scenarios 2:25G-to-25G Link for Switch-to-Server

FAQ for HPE 844471-B21 Compatible DAC SFP28 25G Cable

Q1:Is this 25G SFP28 cable natively backward compatible with 10G SFP+ ports? A:Although SFP28 and SFP+ connectors are physically identical, standard SFP28 25G DAC is programmed as high-speed devices. Most ports that support only 10G cannot recognize 25G-coded cables due to a mismatch in EEPROM identifiers. Most Dell S-Series 25G ports support dual-speed operation at 10G and 25G.

Q2:How far can I run a SFP28 25G DAC cable?A:Because DAC cables are made of dual-core copper wire, they are relatively heavy and experience signal attenuation at a faster rate than fiber optic cables; therefore, the actual transmission distance for SFP28 25G DAC cable is limited to 7 meters or less.

Q3:What is the power consumption of this passive SFP28 25G DAC compared to 25G SR optics? A: HYTOPTODEVICE passive 25G DAC consumes near zero power (≤0.5W) and generates no heat. By comparison, a pair of 25G SR fiber optical transceivers consumes approximately 1.5W to 2.0W of power. For a rack containing 48 servers, switching to the HYTOPTODEVICE 25G DAC can save nearly 100W of power and significantly reduce the cooling load.

Q4:Will this 25G cable cause an "Unsupported Transceiver" error in HPE switches?A:No. DAC Manufacturer China HYTOPTODEVICE uses precise HPE EEPROM coding. Your device will recognize this 25g sfp28 cable as a genuine HPE 844471-B21, ensuring 100% compatibility.

Q5:Does 25G SFP28 DAC use Multi-mode or Single-mode fiber?A:Neither. The DAC(Direct-Attach Copper) is a copper cable. using a twinaxial copper architecture (Twinax) to transmit electrical signals directly, no light signals.There are not lasers or optical glass in DAC cable,  it is much cheaper than fiber optics.

Q6:Where to buy 25G SFP28 DAC cable?A:There are many factories that produce and sell  passive DAC, but DAC manufacturer china HYTOPTODEVICE is the excellent provider: a source factory, fully controllable process, reliable performance, 100% compatible, sufficient inventory, fast delivery.

Q7:Is 25G SFP28 DAC hot-swappable?A:HYTOPTODEVICE SFP28 25G DAC is hot-pluggable, hot Pluggable SFP28 Compliant.you can plug or unplug the passive DAC, while the device is powered on without damaging the hardware.

Q8:who makes the best 25G SFP28 DAC cable?A: Transceiver Manufacturer China HYTOPTODEVICE is the excellent provider.Sorce factory,reliable quality, 100% compatibiltiy.fast delivery and quick response.HYTOPTODEVICE send a tool that allows you to re-program the compatibility of your cables yourself.

Q9:What is the difference between 24AWG and 26AWG for a 5-meter 25G SFP28 DAC cable？A: The main difference lies in signal integrity. 24 AWG cables have a larger cross-sectional area, which significantly reduces resistance. For a 5-meter SFP+ copper cable, the eye diagram of a 24 AWG cable is “clearer” than that of a 26 AWG cable, thereby providing better electromagnetic interference shielding and more stable performance in high-density, high-interference data center environments.

Q10:What is the difference between "Passive" and "Active" DAC?There are distinct differences between Passive and Active DAC.The Passive DAC has no signal amplification. its lengths is under 7m. With zero power consumptions,it cost is cheaper. The Active DAC contains a chip to boost the signal. Used for slightly longer copper runs (up to 10m-15m) and is generally thinner/more flexible.

Q11:Can I plug a 25G DAC into a 10G SFP port?A:No. SFP28 (25G) ports can often accept 10G transceivers, but a 10G SFP port cannot scale up to recognize a 25G DAC cable. You should Make sure the cable speed matches the port with the lowest rated speed.

Quality Assurance：Your Trusted Optical Transceiver Source

 HYTOPTODEVICE is a vertically integrated manufacturer of high-performance optical transceivers. By controlling core materials at the source, we ensure every SFP module meets the highest standards of reliability and customization.

• Vertical Integration: In-house core material production ensures a stable, self-sufficient supply chain for all optical modules.

• Total Traceability: End-to-end oversight from raw components to final transceiver assembly guarantees 100% controllability.

• Bespoke Solutions: Expert-led R&D provides customized SFP transceiver designs tailored to your specific technical needs.

• 24-Hour Response: Our technical team guarantees a primary response to any inquiry or quality concern within 24 hours.

Carrier-Grade Quality. Factory-Direct Control. Rapid Response.

Quality Certification & Compliance：

 At HYTOPTODEVICE, our quality commitment is backed by industry-standard validations. From fiber optical transceiver manufacturing to final inspection, our processes ensure global compliance and reliability.

We adhere to rigorous standards for our SFP modules and network solutions:

• ISO 9001: Certified quality management and production consistency.

• CE & FCC: Fully compliant for seamless Global Market Access.

• RoHS: Committed to environmental responsibility and hazardous material control.

• Proven Reliability: Rigorous testing to reduce compliance risk and ensure safety.

Certified Quality. Global Standards. Guaranteed Performance.

Rigorous Industrial Product Testing：

   

100% 3rd Party Compatible：

Partial Test Demonstration：

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